Composite cylinder head



July 28, 1936.

x COMPOSITE CYLINDER HEAD Filed Aug. 15, 1934 2 Sheets-Sheet l INVENTORfkmk Jam/m6 iTTORNEY F. JARDINE, $049,205

y 1 5- F. JARDINE COMPOSITE CYLINDER HEAD File d Aug. 15, 1934' 2Sheets-Sheet 2 INvENfoR [Ta/7k Jhz/wc Patented July 28, 1936 PATENToFFica 2,049,205 COMPOSITE CYLINDER HEAD Application August 15, 1934,Serial No. 739,918

3 Claims. (Cl. 123-473) The invention relates to cylinder heads forinternal combustion engines. It relates particularly to cylinder headsof this nature of composite design, built up from at least two difierentmetals which are characterized by a wide Variation in their respectivephysical properties.

Internal combustion engines using light oils for fuel are nowuniversally familiar and are available to the public in a great varietyof designs.

l'O Their most common use lies in the automotive engineering field.Their development in the last thirty years has been rapid andoutstanding. Nevertheless there is still ample room for improvement inefliciency as measured by the rela- 15 tion of energy output to input.One of the prin cipal difliculties encountered by engineers centersaround the problem of dissipation of ex cess heat generated duringcombustion of the fuel Most internal combustion engines used in auto- 20mobiles operate most efliciently at a critical combustion chamber walltemperature characteristic of the engine design but usually varyingbetween 300 F. and 700 F. The great majority of such engines are cooledby a circulating fluid, usually water, held in close contact with theupper parts of the cylinder and the cylinder heads by suitable jacketingarrangements. The proper design of cylinder head should successfullyassure two objectives, namely, maintenance of a proper com- 30 bustionchamber temperature, and even distribution of generated heat.

Accordingly, the prime object of the present invention is the design ofa cylinder head such that excess heat will be evenly and efiicientlydis- 35 sipated.

Two main types of cylinder head for internal combustion engines havebeen in use heretofore which I term unitary and composite. By uni-- taryI refer to a cylinder head cast or formed in 40 one piece from onemetal, usually having integrally formed passages for cooling fluid or,perhaps, cooling fins for air cooling action. By composite I mean abuilt-up cylinder head of two or more collaborating parts, possibly ofthe same 45 metal with cooling passages between, possibly of two or moredifierent metals comprising an inner liner adjacent the combustionchamber made from heavy metal of relatively high strength, combined withan outer portion of a lighter metal 50 of relatively high heatconductivity, the outer portion being sometimes provided with coolingfins or containing fluid passages between the two components of thehead. These latter composite heads, while representing an improvementover 55 the older art, suffered with the older art a commondisadvantage, namely, while the heat might be dissipated rapidly it wasnot dissipated evenly and it is quite possible to err on the side of toomuch heat dissipation as too little. The design disclosed hereinbelowpermits the heat to be dis- 5 tributed to a surprisingly even extent andthe dissipation of heat may be quantitatively regulated in the mannerhereinafter shown.

One adaptation of my invention is illustrated in the accompanyingdrawings, in which Fig. 1 represents a plan view of part of a cylinderhead including the upper contour of the several combustion chambers;

Fig. 2 represents a section taken on the line IIII of Fig. 1;

Fig. 3 represents a section taken on the line III-Ill of Fig. 1;

Fig. 4 represents a plan view of part of a cylinder head including theupper contour of several combustion chambers showing individual liners;

Fig. 5 represents a section taken on the line VV of Fig. 4; and

Fig. 6 represents a section taken on the line VIVI of Fig. 4.

As shown in the drawings the cylinder head is built up from two members,II and I2, ll representing an inner liner of metal adjacent to thecombustion chamber and forming the upper wall thereof, and I2representing an outer member which serves as a brace or support for theinner member II and which may also contain the water passages, coolingfins, or other means of heat radiation.

The inner liner II I form from aluminum or aluminum alloy or other metalof high heat conductivity. The outer member I! forming the major portionof the cylinder head I form from a metal of sufficient strength tosupport the forces bearing on the liner, and of relatively low heatconductivity as compared with the metal 0 of the liner II. The liner Hand head [2 fit snugly together and may be held in place on the cylinderblock by suitable stud bolts or other arrangement. The liner may even beformed to a satisfactory fit by casting it in place in a mold in whichthe member l2 forms one wall of the casting cavity and the liner ll maybe formed to any suitable thickness by properly forming the castingcavity in manner well known in the art. This is merely one method offorming the liner since it may be forged or pressed in suitably formeddies or cast in sand or metal molds as best suits the occasion. Theliner may, and preferably does, cover more than one cylinder since theusual automobile engine has four or more cylinders in line in one block.In most cases it is desirable for proper heat distribution that theliner extend the full length of the engine block and form the finishedsurface which contacts the cylinder block in an assembled engine, asshown in Figs. 1, 2, and 3. One modification of my invention, however,contemplates the use of an individual liner for each combustion chamberin a multi-cylinder engine, as shown in Figs. 4, 5, and 6. In thislatter case the-liner ll preferably does not extend further than thecombustion chamber and the thickness thereof is finished with and formsa part of the surface which has to contact the cylinder block.

Cylinder heads as designed up until the time of the present inventionwere of varying section thickness necessitated by certain factors suchas presence of water chambers, spark plug bosses, valve guide bosses,etc. The member adjacent the combustion chamber in a composite designwas invariably made of a ferrous metal alloy to withstand heat andpressure while the light alloys, if used at all, were used as outermembers to radiate the excess heat. The ferrous metal is relatively apoor heat conductor and certain sections of varying thickness causedlocal hot-spots" by reason by inability of the ferrous metal to conductthe heat away evenly and rapidly. This sometimes became serious enoughto cause pre-ignition or severe local carbonization.

As a result of my invention wherein a liner of metal of high heatconductivity, such as aluminum or an aluminum alloy, is placed next tothe combustion chamber, the heat generated is immediately distributedevenly over. the whole head of the engine, and especially over eachseparate combustion chamber so that local hot-spots are eliminated. Theassembly of course may be pierced for spark plugs or other requiredapertures may be formed therein.

Since the high conductivity liner, or "heat equalizer", is backed up bya ferrous metal outer head, the heat flow from the combustion chamber,while equalized, is moderated, so that the engine is not subjected tothe extreme of too rapid heat abstraction. Where liquid cooling is usedthe liquid passages may be permitted to contact,

, if desired, with the inner liner at points not immediately above thecombustion chamber, or, if desired, the water passages may be completelycontained within the ferrous metal head. By suitably varying thethickness of the high heat conductivity liner, varying degrees of heatabstraction may be obtained to suit the proper and desired workingtemperature of the motor. The liner may be fitted snugly to the ferrousmetal head with a metal-to-metal contact or the members may containtherebetween a flller or cement of any material of desired thermalconductivity.

In addition to its function in restraining an immoderate heat flow fromthe combustion chamber the outer member in my combination cylinder headserves as a backing-up or strengthening member to support the innerliner under the severe variable stresses set up during the operation ofthe motor. For this reason the liner may be made of any desired sectionthickness with consequent positive control of the heat flow. A liner ofmoderate thickness, for instance about to inch, should be adequate forordinary requirements. It may, however, be thinner or thicker than thesedimensions.

In this specification and the appended claims wherever the term aluminumis used it'contemplates not only the metal of commercial purity, butalso alloys thereof with other metals.

I claim:

1. A cylinder head for an internal combustion engine having a pluralityof cylinders comprising an external member formed of a metal ofrelatively low heat conductivity and provided with heat-abstractingmeans, an internal liner of aluminum adapted to form a substantialportion of the combustion chamber of each cylinder and forming a path ofhigh heat conductivity from cylinder to cylinder whereby the temperatureof the individual combustion chambers is substantlally equalized, saidliner being in close contact with said external member and adapteduniformly to conduct the heat of combustion to said external member.

2. "A cylinder. head for an internal combustion engine having aplurality of cylinders, comprising an external ferrous supporting memberprovided with passages for the circulation of a fluid cooling medium, aninternal liner of aluminum adapted to form a substantial portion of thecombustion chamber of each cylinder and forming a path of high heatconductivity between adjacent chambers whereby the temperature of theindividual combustion chambers is substantially equalized, said linerbeing in close contact with said external member and adapted uniformlyto conduct the heat of combustion to said external member.

3. An internal combustion engine having a plurality of cylinders,meansfor equalizing the heat of the combustion chambers of the severalcylin- Y ders comprising an aluminum liner of substantial FRANK JARDINE.

